SUFFOLK - Developing technology to help military troops navigate in urban settings -- including avoiding "friendly fire" and tracking enemy forces inside buildings -- is the focus of a new effort by the Joint Forces Command here.

The military routinely uses satellite-based global positioning systems in warfare, but that often fails in urban environments, where signals are blocked by multi story buildings, said Richard Carter, science and technology adviser for the Joint Urban Operations Office in Suffolk.

The aim is to develop a hybrid tracking system using various navigation sensors and radio waves that could be used when GPS isn't available, such as inside buildings or underground in tunnels or in caves.

It would be developed under an agreement signed this week by the Joint Forces Command and defense contractor L-3 Communications' Interstate Electronics Corp.

The plan is to get several prototypes to the Marine Corps for testing by May 2008, said Jim Benson, the director of advanced technology for the Anaheim, Calif.-based Interstate Electronics.

Under the cooperative research and development agreement, the company is not getting paid by the government. But if a commercial product spins out of the joint effort, the company could sell it to the military.

The cooperative agreement is the seventh that the Joint Forces Command has signed with industry partners since 2005, covering a range of technologies.

Benson said his company has a $2 million contract with the Department of Homeland Security to develop a similar system that could be used by emergency first responders, such as firefighters and police.

"Our technology was essentially validated by the Department of Homeland Security," Benson said. "It's in development still, but our plan now with the Joint Forces folks is to adapt that technology to military use."

The effort has two purposes -- to help field commanders keep track of individual troops as they carry out missions and to allow Soldiers to monitor their own locations. Benson said it could help eliminate "friendly fire" deaths, citing the highly publicized case involving Pat Tillman, an Army Ranger killed in Afghanistan by fellow Soldiers.

Part of the research will be on how to package the technology into gear that could be easily carried and used by Soldiers in the field, such as a hand-held device, said Darrel Johnson, a General Dynamics Corp. contractor who is a technical expert for the Joint Urban Operations Office.

"This capability would be very functional in locating a downed or missing person or in a possible hostage situation -- the list goes on and on," Johnson said. "Added to a Soldier's tool bag, this is a capability that's going to help them remain safer."